1. Field of the Invention
Apparatuses and methods consistent with the present invention relate to a display apparatus, and more particularly, to driving a liquid crystal display to improve the quality of moving pictures.
2. Description of the Related Art
FIG. 1A shows a graph illustrating response values with respect to different drive voltages in a related art liquid crystal display (LCD) and FIG. 1B shows a graph illustrating response values with respect to an overdrive voltage in the related art LCD.
Because drive voltages and response values have difference units, they are first normalized and then plotted as illustrated in FIGS. 1A and 1B. FIG. 1A illustrates an output luminance value of LCD pixels when two different drive voltages are applied to the LCD. A response value is an output luminance value of the LCD panel. Generally, a drive voltage is a voltage corresponding to a video or image signal and is applied to the LCD. On the other hand, an image signal and a drive voltage in the present invention respectively denote an image signal and a drive voltage corresponding to each pixel of a frame.
Referring to FIG. 1A, a response value reaches a target response value after a drive voltage changes and three frames have passed. Accordingly, when a response speed of a pixel in the LCD is slow, an artifact, such as a ghost image or an edge-blurred image, occurs in a moving picture having many movements.
In FIG. 1A, a slope of the response value is higher when the drive voltage is higher, as shown by drive voltages 1 and 2. Accordingly, to accelerate the response speed, an overdrive voltage is used.
FIG. 1B illustrates an output luminance value of LCD pixels when an overdrive voltage is applied to the LCD. When the overdrive voltage is applied in a frame period, for example, frame 2, the LCD response speed increases in the corresponding frame period. When the overdrive voltage changes to an ordinary drive voltage at frame 3, an output response value maintains the target response value. Accordingly, when the overdrive voltage is applied in a frame period, the response speed can be increased. However, a phenomenon, such as edge-blur cannot be completely removed only by applying the overdrive voltage to the LCD.